When I change the interface settings to USB TMC, the device is stated as “Unknown USB Device (Device Descriptor Request Failed)”
In the device manager I can see a COM interface, which should not happen if "TMC" is set.
On my PC I have installed VISA and the drivers for the HO732 interface board.
What goes wrong?
This is a typical problem with windows.
If the drivers for the HO732 are installed and a VCP connection has been established before, windows seems to store that and try to use the same driver for a TMC connection.
But that is the wrong driver and the connection fails.
The following procedure solves the problem:
At first please check if the path
C:\Program Files\IVI Foundation\VISA\IVI USB Staging
is existing on the PC. That is the correct driver for a TMC connection.
On the HMO3000 select USB TMC and connect it to the PC
Open the device manager on your PC.
As soon the HMO3000 is connected, a COM port with an exclamation mark is shown as interface
Do a right click on that COM port and select "uninstall" - very important: set the tick mark to remove the driver software!
Usually now the correct driver is installed automatically.
If the driver is not found, direct the installer to the path:
C:\Program Files\IVI Foundation\VISA\IVI USB Staging
